Upgrading fused benzenoid ring hydrocarbons



United States Patent UPGRADING FUSED BENZENOID RING HYDROCARBONS No Drawing. Application March 26, 1956 Serial N0. 573,589

2' Claims. Cl. 260-411 This invention relates to the reaction of fused benzenoid ring hydrocarbons with methylcyclohexane toproduce compounds having a higher hydrogen content than said fused benzenoid ring hydrocarbon.

In the petroleum industry, large amounts of aromatic hydrocarbons containing 2 or more fused benzenoid rings are being produced. These materials are chiefly products of hydrocarbon conversion processes utilizing solid catalysts such as silica alumina, natural clays and silica magnesia; some are produced from the catalytic reforming operations. These fused benzenoid ring hydrocarbons are refractory materials and are difficult to crack further. When these compounds do break up, they tend to form coke and gas with low yields of the desired gasoline boiling range or light gas oil boiling range hydrocarbons. Hydrogenation of the compounds and/or alkylation of these compounds produce alkyl substituents which have a favorable effect on the cracking yields owing to the presence of added hydrogen. The continued large ,demand for high octane gasoline makes it imperative that the high boiling cycle stocks produced from the catalytic cracking of the virgin gas oils be made amenable to further catalytic cracking with yield of gasoline range aromatic hydrocarbons.

An object of the invention is a process for increasing the hydrogen content of fused benzenoid ring hydrocarbons. Another object is the treatment of hydrocarbon feeds, such as high boiling ga's oils, to increase the hydrogen content. Yet another object is a method of upgrading heavy gas oils derived from catalytic cracking operations to make possible more usable catalytic cracking feed. Other objects will become apparent in the course of the detailed description.

In'the process of this invention, a hydrocarbon feed containing an aromatic hydrocarbon having at least two fused benzenoid rings is contacted with a methylcyclohexane in the presence of liquid HF catalyst under conditions of temperature and time such that a reaction takes place between the methylcyclohexane and said aromatic hydrocarbon to produce a hydrocarbon product having a hydrogen content higher than said aromatic hydro may be naphthene or olefin in nature. Examples of various' fused benzenoid ring aromatic hydrocarbons which are suitable for the process are: Naphthalene, anthracene, phenanthrene, pyrene, chrysene, pentacene, benzopyrene. perylene, coronene, picene and hexacene; the various methyl, ethyl, propyl, butyl, etc. derivatives of these;

the ethenyl, propenyl and butenyl derivatives of these;

'ice

acenaphthene, tethracene, hexahydropyrene, beuzathrene, choloanthrene, rubicene, etc. These defined fused benzenoid ring hydrocarbons may be charged to the process as individual compounds or mixtures of individual compounds, in the absence of other types of hydrocarbons. Also, the defined charge hydrocarbons may be introduced into the reaction zone in admixture with mono-nuclear aromatic hydrocarbons, such as benzene, toluene or fused ring hydrocarbons such as the indanes or hydronaphthalenes. Also, the defined charge hydrocarbons may be utilized in combination with paraflinic hydrocarbons or olefinic hydrocarbons. -Since the principal object of the invention is the upgrading of gas oils to make them suitable for catalytic cracking operation charge, the preferred feeds are cracked gas oils containing appreciable amounts of the defined fused benzenoid ring hydrocarbons. The cracked gas oils, either thermally cracked or catalytically cracked, contain particularly large amounts of these hydrocarbons. The so-called heavy gas oils which largely boil over the range of about 500 F. to 750 R, which have been derived from a catalytic cracking operation, are particularly suitable feeds to the proc ess.

The other reactant is a methylcyclohexane.

The presence of some methylcyclohexane will result in an increase of the hydrogen content of the defined aromatic hydrocarbon charge. Theoretically about 2 moles of methylcyclohexane are required per mole of defined aromatic hydrocarbon in the hydrocarbon feed. In general, between about 1 and about 20 moles of methylcyclohexane are present in the reaction zone per mole of the defined fused benzenoid ring aromatic hydrocarbon present therein; preferably between about 3 and 5 moles of methylcyclohexane are used per mole of defined aromatic hydrocarbon present.

The reaction takes place in the presence of a liquid hydrogen fluoride catalyst. The reaction is carried out under substantially anhydrous conditions. Usually the hydrogen fluoride catalyst should not contain more than about 2 or 3 weight percent of water. Commercial anhydrous hydrofluoric acid is particularly suitable for use as the HF catalyst. The reaction requires the presence of liquid hydrogen fluoride and sufficient pressure must be maintained on the reaction zone to keep the HF in the liquid state. 7

The catalytic activity of the liquid HF is promoted by the presence of boron trifiuoride. Small amounts of BF will have some appreciable effect in increasing the catalytic activity. In general, between about 0.5 and 5 moles of BP will be used per mole of defined aromatic hydrocarbon present in the reaction zone. Preferably between about 1 and 2 moles of BF are present per mole of defined aromatic hydrocarbon present. The liquid HF is present in an amount between about 50 and 500 volume percent, based on defined aromatic hydrocarbon present in the reaction zone. More usually between about 100 and 200 volume percent, based on defined aromatic hydrocarbon, is utilized.

The reaction requires a time and temperature relationship which is dependent upon the activity of the catalyst system. When using liquid HF alone or liquid HF promoted with minor amounts of BF the reaction is carried out at a temperature between about C. and 200 C. The catalyst and the reactants are contacted at these temperatures for a time ranging between about 1 minute and about 8, hours. The higher temperatures permit shorter times of contacting or, conversely, the longer times correspond to the lower temperatures of contacting. When using liquid HF, under these condi- Patented Apr. 28, 1959 At thevcompletion of-the reaction, the liquid HF catalyst is separateiusually by decantation, from the hydrocarbon phase which-contains the unreacted methylcyclohexane and the hydrocarbon-product. Thehy rocarbon product-is characterized by .a hydrogen content higher than that -.of the-hydrocarbon vfeed to :the reactiouzoue.

Also, thexcatalystmaybe separated ,from the hydrocarbon product and methylcyclohexane ,bydistilling away the I-IFa-nd ;BF ,,-ifanyhas been used.

The results obtainable .with the process .of the invention are illustrated by the following working examples.

These examples were obtained by utilizing an autoclave provided with a mechanical stirrer.

introduced therein. The contents of the autoclave were heated to the desired temperature and vigorously agitated for the selected contacting time. At the completion of this time, the contents were cooled and the acid phase separated. The acid phase was quenched in cold water. The hydrocarbon phase was neutralized. Any hydrocarbon recovered from the acid phase was added to the neutralized hydrocarbon phase. The total hydrocarbons were distilled to remove unreacted methylcyclohexane and were then cut up into narrow boiling range fractions. These narrow boiling range fractions were inspected for physical characteristics, such as refractive index, and were analyzed byinfrared spectrometry for hydrocarbon class content.

In Table I there are set outthe results of runs on the reaction of B-methylnaphthalene with methylcyclohexane and in one run without methylcyclohexane. Inrun No. A, theresults show that the methylnaphthalene extensive- .ly cracked even at the low temperature of 20 C. Run No. B was carried out with methylcyclohexane as the isoparaflin. In run No. C,}no BF was used but a high temperature was used instead. Theruns show that while the reaction was carried out considerable tar formation did take place under these conditions.

There is set out in Table II the results of reacting a heavy catalytic cycle oil derived from the cracking of .gas oils over a silica alumina catalyst utilizing' methylcyclohexane. Also, a run Wasmade on the extract hydrocarbons obtained by the liquid S extraction of this heavy catalytic cycle oil. Runs No. Band B were carried out on the gas oil itself. Run No. D was carried out at 76 C.

TABLE I Hydroalkylatzon of beta-methylnaphthalene [Reaction time-4 hours] Run N 0 A B C Isoparaiiu None Methylcy- Methylcyclohexane clohexane Moles per mole Methylnaph 1 1 HF, moles'per mole Methyluaph 13 '20 20 BFg, molesper mole, Methylnaph 1. 4 1. 0 Temperature, 0 20 100 Product Distribution, Wt. Percent (011 isoparafim-free basis):

Methylnaphthalene 53 3 21 Alkylmethylnaphthalene 13 36 24 Tetralins, indanes, and alkylbenzenes 4 51 45 Tar .4. .i .30 10 23 Isoparafiin consumed, percent 75 The reactants were introduced into the autoclave and the catalyst was then.

TABLE II 1 Run N o D E I Petroleum Stock H000 HCGO HCCOX Wt. g 124 V 121 131 Methylcyclohexane, Wt. g. 106 106 108 Wt. Percent MGH in Fee 46.1 46. 7 44. 6 400 400 400 a, 64 73 86 76 '22 25 Time, Min 4. 300 180 Product Distribution, Wt. Percent:

Butane 3 0 Methylcyclohexane. 20 .43. 4 40.5 Gasoline- 18 0 Gas OiL- .59 56. 6 59. 5 Inspections: v

m of Petroleum Sto'ek 115163 1. 5163 1. 5890 no of Gas Oil Fraction of Prcd- 1 not 1.5230 1.5130 1. 5848 m of Gasoline Fraction of 1 Product 1. 4450 for a time of 3 hours. The results show that a considerable amount of .gasoline boiling range material was produced in addition to-the methylcyclohexane which was not reacted. Run No. E'shows thatgasoline formation can be suppressed by operating-at lower temperature for a longer time. ,Run No. F,.shows that some improve rnent can be obtained byreacting solvent extractfrom a catalytic gas oil with methylcyclohexaue.

RUN NO. G

In this run, one batch of liquid'I-IF--BF catalyst was used to treat successively 36 batches of heavy catalytic cycle oil with methylcyclohexane asi'the isoparafiin. Each batch of hydrocarbon feed was treated for 3 hours at 60 C. The 'rafiinat-e or hydrocarbon phase was then decanted away from the acid phase and another batch of fresh hydrocarbon feed introduced into the reactor. After 36 batches, the'hydrocarbon phases were intermingled to form a single product mixture. The acid phase was decomposed with cold water and the dissolved hydrocarbons separated from the aqueous layer. The extract was analyzed for sulfur content and also fractionated intoS fractions. A complete description of the operation is set out below. By the use of the technique of this run, it is possible to produce a materialwhich is of fair quality for catalytic cracking charge with only a small consumption of methylcyclohexane.

Operation: 36 batches hydrocarbon, 20.0 g. each. Each batch treated for 3 hours at 601 .C. Rafiinate wasthen removed andanotherbatchadded.

Wt. g. Product Balance H000 Loss to Ext. Laycr=13.5%. MCH Gonsumption=5%.

Wt percent, S 1:22

BOILING RANGE OF RAFFINATE SAME AS FEED (250-380 0.) [Composition of extract.]

Out No. Wt. B.P., nu

Percent C.

13 365-440 Resin 13 440-485 Resin 9 485-520 Resin 12 52 Coke Thus having described the invention, what is claimed is:

1. A process which comprises contacting, under substantially anhydrous conditions, a hydrocarbon feed containing an aromatic hydrocarbon having at least two fused benzenoid rings and a methylcyclohexane, in a molar ratio of said cyclohexane to said aromatic hydrocarbon of at least about 2, with a catalyst consisting essentially of liquid HF, in an amount between about 50 and 500 volume percent based on said aromatic hydrocarbon, and BF in an amount from about 1 to 5 moles per mole of said aromatic hydrocarbon, at a temperature between about 15 C. and 100 C. for a time between about 5 minutes and 3 hours, the longer times corresponding to the lower temperatures, separating an acid phase from a hydrocarbon phase, and separating unreacted methylcyclohexane from hydrocarbon product, which product is characterized by a hydrogen content higher than said feed.

2. The process of claim 1 wherein said feed is a catalytically cracked gas oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,367,474 Stewart Ian. 16, 1945 2,433,020 Becker Dec. 23, 1947 2,467,920 Voge et al Apr. 19, 1949 2,717,864 Charlet et al Sept. 13, 1955 

1. A PROCESS WHICH COMPRISES CONTACTING, UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS, A HYDROCARBON FEED CONTAINING AN AROMATIC HYDROCARBON HAVING AT LEAST TWO FUSED BENZENOID RINGS AND A METHYLCYCLOHEXANE, IN A MOLAR RATIO OF SAID CYCLOHEXANE TO SAID AROMATIC HYDROCARBON OF AT LEAST ABOUT 2, WITH A CATALYST CONSISTING ESSENTIALLY OF LIQUID HF, IN AN AMOUNT BETWEEN ABOUT 50 AND 500 VOLUME PRECENT BASED ON SAID AROMATIC HYDROCARON, AND BF3, IN AN AMOUNT FROM ABOUT 1 TO 5 MOLES PER MOLE OF SAID AROMATIC HYDROCARBON, AT A TEMPERATURE BETWEEN ABOUT 15*C. AND 100*C. FOR A TIME BETWEEN ABOUT 5 MINUTES AND 3 HOURS, THE LONGER TIMES CORRESPONDING TO THE LOWER TEMPERATURES, SEPARATING AN ACID PHASE FROM A HYDROCARBON PHASE, AND SEPARATING UNREACTEE METHYLCYCLOHEXANE FROM HYDROCARBON PRODUCT, WHICH PRODUCT IS CHARACTERIZED BY A HYDROGEN CONTENT HIGHER THAN SAID FEED. 